provided for indoor or outdoors use. Built from high quality carbon steel, the surface is zinc for good rust resistance. Each nut has two Style parts that allow you to easily adjust and tighten with your hands or with tools. These butterfly nuts can be used to help make fast and easy adjustments without fear of stress, damage or Abrasion. Specification: Material: Carbon steel Finish: Zincupel, net size: M6 x 1 mm Size: 27 (+/- 1.0) MM x 11mm x 11.5mm/1.06 x 0.43 x 0.45 (LODH) Contents of the packaging: 20 x Butterfly nuts